Converting absolute path to relative

What is best way to convert absolute path to relative path by javascript or jquery ?

for example consider as below :

"http://localhost:2011/Content/Images/Product/Large/3.jpg" 

to

 "/Con开发者_如何学Gotent/Images/Product/Large/3.jpg" 

Use the trick that <a> elements contain location properties.

$("<a href='http://localhost:2011/Content/Images/Product/Large/3.jpg'>")
  .prop("pathname");

Just use window.location.pathname